An optical time domain reflectometer (OTDR) has been used for detecting fault such as break, bend in an optical fiber. The amount of optical fibers being laid has rapidly increased with an increase in the capacity of mobile traffic. However, there are an increasing number of cases where operators inexperienced in handling of optical fiber cables are using an OTDR. Therefore, for OTDR, analysis results being easily understandable and an intuitive operation are required (for example, refer to Non-patent Document 1).
FIG. 11 shows an example of the screen configuration disclosed in Non-patent Document 1. The screen is configured to include icons indicating events Iv18 to Iv24 that are failure points of the optical fiber detected by the analysis, details of an event Iv21 that is an event of interest (location where the operator wants to check the line), and a hard key (not shown) for changing an event of interest provided outside a display unit 113. In addition, the classification of failures is shown by the symbol in each icon, an event of interest is displayed in an enlarged manner or displayed so as to be surrounded by a frame, and failure point information (distance, loss, and failure classification) or the like is displayed in an information display region AINF. In a case where there is a failure, the operator changes the event of interest by operating the hard key in order to identify the loss and the distance of the failure point.